[cups.general] Should the CUPS Raster output device of Ghostscript output compressed or uncompressed Raster data?

Johannes Meixner jsmeix at suse.de
Wed Jul 7 00:43:35 PDT 2010


Hello,

On Jul 6 09:57 Heino Goldenstein wrote (shortened):
> Am Dienstag, 6. Juli 2010 02:53 schrieb Michael R Sweet:
>
>> Compressing raster data on-system has a serious performance impact, more
>> than sending uncompressed data over the pipe.
>
> this point is full understand, but in our use case the cups-raster data is
> transferred off-system via the printer connection (ethernet, usb,
> centronics, ...).

In general the final data transfer belongs to the backend.

Does your particular printer device really get CUPS raster data?

Usually the printer device gets whatever printer-specific data
which is generated by a printer-specific driver program
from the CUPS raster data.
I.e. the driver gets via pipe CUPS raster data and outputs via pipe
printer-specific data which is sent to the device by the backend.

Therefore you may need compression of the printer-specific data
but no compression of the CUPS raster data.

You may have a look at
http://en.opensuse.org/SDB:CUPS_in_a_Nutshell
"The Filter" versus "The Backends".

Perhaps it is easiest to add one more filter step
which does only whatever compression you need for your
particular printer device and printer connection.
You may have a look at
http://en.opensuse.org/SDB:Using_Your_Own_Filters_to_Print_with_CUPS
in particular
"Adding Additional Filter Stages to the Default CUPS Filter System"


Kind Regards
Johannes Meixner
-- 
SUSE LINUX Products GmbH, Maxfeldstrasse 5, 90409 Nuernberg, Germany
AG Nuernberg, HRB 16746, GF: Markus Rex





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